Generally, in the art of sharpening knives it is the practice to run the knife blade along the sharpener. That is the means to sharpen the knife, such as a grinding stone, a grinding wheel or a die grinder, is usually permanently positioned and the edge of the knife blade is moved along the sharpening means.
This requires a person to hold the knife and maintain the contact between the knife's edge and the grinding surface while that person is moving the edge of the knife along the grinding surface. A human cannot guarantee that the same amount of pressure is constantly applied to the knife's edge while grinding it.
Often this method of sharpening leads to a knife which is sharpened more at some points along the blade and less at others. This is a result of the uncontrollable variance in pressure inherent in this method.
A similar technique has been employed with knives or blades which are integral to a machine such as a saw or some type of cutting or slicing apparatus.
In U.S. Pat. No. 3,958,478, issued to Camper, a commodity slicing machine is provided with a non-rotatable honing stone which sharpens the knife as the knife rotates in the machine.
Another device where a sharpener device is part of a cutting machine is seen in the Pearl U.S. Pat. No. 4,033,214. This patent provides for a sharpener which hones the blades of a pattern cutting machine by rotating the blades against a stationary sharpener.
The Steiner U.S. Pat. No. 4,173,846 discloses a sharpening device to be mounted on the frame of an orbital saw. The blade is sharpened when it is rotated in contact with the stationary sharpener.